A PPR Context can be removed from the database using the Delete in Database command in the Lifecycle Toolbar, but  the Whole structure propagation option is not available for PPR Contexts.  

There is workarounds to bypass this limitation:

1. Insert PPR Context into a Product.

2. In the Search Result window, select the newly created Product, click Delete. Select the Whole structure option to propagate the delete to the entire structure. 

3. Whole Product structure containing PPR Context(s) will be deleted when you confirm the operation.